I'm the developer of an application that is currently on the Mac App Store. I'm trying to download my own application so that I can test out the binary that is on the store. (As opposed to running it in Xcode.)

I have purchased my own app in the app store previously, but then deleted it. (So that I could install a different version for testing.) Now, the App Store thinks that the application is still installed, even though it is not. (I deleted the development version when I was finished using it.)

I have removed all instances of the application from:

/Applications

~/Downloads

But the app is marked as "Installed" in the App Store, and it doesn't show up in my purchases. Is there a trick to get my binary re-installed?

It could be that the App Store interface sees your development version(s) as the installed copy. LaunchServices doesn't care if your app is in the /Applications folder or buried in your Xcode build directory. See also.

On Snow Leopard, I not only had to run the command in Craig's answer, I also had to make sure that Spotlight was up to date and did not show the app in question to still be on the computer.

You can refresh particular folders in Spotlight's index using the mdimport command. So to refresh the /Applications folder:

mdimport /Applications

I had a Lion partition as well as a SL partition on the machine. Spotlight was set up to index everything on both partitions, and there was a version of the app in question on my Lion partition. I added the entire Lion partition to Spotlight's ignore list, then ran the command in @Craig's answer, and everything worked. Just running the command in @Craig's answer was not enough for me.